Silent chain



Patented Sept'. 8., 1931 l* UNITED STATES PATENT oicE CHARLIE CARL ROTHMAN, OF INDIANAPOLIS, INDIANA, ASSIGNOR TO LINK-BELT COMPANY, OF CHICAGO, ILLINOIS, .A CORPORATION OF ILLINOIS SILENT CHAIN `App1cation led December This invention relates to improvements in silent chain construction, and'more particularly to improvements in the articulating joints by which the links are united. u

The principal object of the invention 1s to provide a novel'articulating joint having desirable features of simplicity and durability and which shall render the chain relatively quiet in operation. j

A further object of the invention is the provision of a truly flexible oint which shall at the same time be free from backlash or looseness, thus making the chain adaptable y to widely varying operating conditions.

The invention will be more readily understood by reference to the accompanying drawings, in which: l

Figure l is a fragmentary side elevatlon showing a portion of a chain made in accord,-

ance with my invention;

Fig. 2 is a plan view of the chain; Fig. 3 is a View in perspective of one of the links;

Fig. 4 is a perspective view showing the two elements which constitute each of the pintle pins;

Fig. 5 is an enlarged fragmenary elevation, partly in section, illustrating the detalls of the device, and

Figs. 6, 7, 8 and 9, are, respectively, fragmentary sectional elevations showing modifications within the scope of the invention.

With reference to the drawings, the chain comprises a plurality of links 1 of well known form, each link having at each end a pitch hole 2 and the links being arranged in a plurality of transverse rows or pitches, such as those designated by the reference numerals 3, 4 and 5, with the ends of the links of one pitch overlapping the corresponding ends of the adjacent series so that the said pitch holes are in alignment. The links of each pitch are joined to the links of the adjacent pitch by means of a pair of substantially segmental pin elements 6 and 7 which are passed through the aligned pitch holes 2 of the overlapping links, with their convex sides toward each other, as clearly illustrated in the drawings. These segmental joint members are held in proper relationship to each other and 6, 1928. Serial No. 324,258.

tothe links by lugs 8 projecting from the edges of the pitch holes of the links, and these lugs are so arranged in the pitch holes as to provide in one series of links abutments for the edges of the segmental joint members and in the adjacent series of links clearance for articulation around the joint member of the adjacent pitch.

The joint members 6 and 7 may be retained in position longitudinally in the links by any suitable means, such for example as by making one member of each joint longer than the other and riveting over the end of the longer so that the upset end portions thereof not only overlie and project beyond the edge of the pitch hole, but also overlie the end of the associated joint member. This is clearly shown in Fig. 5 in which the upset or riveted over end of one of the members is indicated by the reference numeral 9.

The aforedescribed device has been found a particularly desirable one not onlyy by reason of the modified rolling action between the associated joint members, but also by reason of the elasticity in the chain which this joint affords. In operation when articulation takes place the convex surfaces of the joint members roll upon each other and the line of contact of these surfaces provides the instantaneous centers of rotation of the adjacent pitch links. The stress in the chain is transferred from one pitch of links to the adjacent pitch by-pressure on the convex sides of the joint members, and by reason of the fact Vthat the major portions of the concave sides of the jointvmembers are unsupported the arch ofthe segments is permitted toV flatten slightly under load and shock to an extent determinable by cross sectional di-' mensions of the segments.v

There may be considerablemodification within the scope of the invention.- It will be noticed for example that in Fig.y 6 the pitch holes of the links are so formed as to provide recesses 10 into which'the'edges of the segmental joint members fit. In Fig. `6 the edges of theV segmental members abut the bottoms of these recesses l0, whereas in Fig. 7 a slight clearance is left at the edges of the seg- Ymental members permitting a slight play or f the seement is self-adjustment of these members in the pitch holes of the links. Also as shown in Fig. 8, it is not necessary to a practice of the invention to have both of the joint members in the segmental form, and one of these may be solid, as indicated l2 without departure from the invention. rlhis arrangement pro-V vides the same rolling action between the elements, and the elasticity is provided by the flattening of the companion segmental element 13.

In Fig. 9 I have illustrated a modification of the means for fixing the joint members longitudinally in the links. ln this., instance a washer 14 is provided having ends shaped to the backs of the long members and adapted forv insertion between the joint niembers of each alternate pitch, rJQhe length of the washer is such that it. fits snugly and tends to push the engaged members apart. The latter members are then riveted over the washer which secures the parts in position. Obviously individual perforated waShcIfS for each of the joints might also be used.

Silent chain constructed with joints designed in accordance with this invention operates with marked quietness. The ointS quickly absorb the periodic vibrations originating at the point of contact of chain links and sprocket teeth, and prevent transmission of sound through the chain. This in turn prevents the augmenting of the original contact sounds, by substantially eliminating resonance in the free strand of chain between sprockets. The flexible joint further cushions all longitudinal components of shock and impact forces which the chain may receive,`

materially reducing the destructive effect of these forces.

l claim:

l. Ah articulating joint for the links, of power chains, which comprises a pair of pin elements each having a convex side and adapted Jfor mounting in the links so that the chain stressesl are transferred from one adjacent link to. another by pressure on said convex sides, at least one of said elements being seg mental in form and being mounted in the links with a substantial portionl of the. concave side unsupported whereby the arch of Y C, permitted to flex inwardly under load and shock. 2. An articulatingpjoint for the links of power chains, which comprises a segmental 2 1 pin element mounted in the links so that the chain stresses are transferred from; one adj acent link to another by pressure on the con- Vex side of said element, said clement having a substantial portion of the concave side unsupported whereby the arch of the segment is permitted to depress under load and shock.

3. An articulating joint fork the links of power chains, which comprises a segmental. pin elementrmounted in the linksv sothat the longitudinal edgesthereof may bear against one of said links and so that the chain stresses are transferred to an adjacent link by pressure on the convex side of the element, said clement having a substantial portion of the concave side thereof unsupported whereby the arch of the segment is permitted to depress under load and shock.

4. An articulating joint for the links of power' chains, which comprises a pair of segmental pin elements mountedin the linksoy a substantial portion of the concave,V side of each element unsupported, the relation of the elements to the links being such that the chain stresses are transferredfrom link to link by pressure onthe convex sides of said elements, and said elements. being flexible whereby the arches of the segments are permitted to depress under load` and shock.

6. A power chain comprising perforated links arranged in overlapping relation with the perforations in alignment,A a segmental pin element extending through said aligned apertures with its longitudinal edges finding a seat on the edges of the aperture of one link and with its convex side constituting an abutment whereby the stresses in the chain are transferred from the one link to the OVBI- lapping link, a substantial portion of the concave side of said clement being iuisupported whereby the arch of the segment is permitted toy 4depress under load and shook..

Y. A silent chain comprising a plurality of sets of apertured links, the links of the adj as cent setsv overlapping with said apertures in substantial alignment, and articulating joints for said sets of linksV each comprisingl` a pair of segmental pin elements, extending through said apertures with their convex sides in abutment and with a substantial' portion of their concave sides unsupported whereby stressesin the chain are transferred from one. set. of links. to. the adjacent set by pressure. upon the convex ments and whereby the arches of said segments are adapted todepress under load and shock. v

8; In a, silent'chain, the combinationof a plurality of sets of apertured links, the links of one set overlapping the links of an adjacent set with the said apertures in aligmnent,y a pair of segmental -pintleipins extending through Said apertures with their convex,

sides in abutment and with a substantial po.r.

sides of said elesol tion of their concave sides unsupported, and

means in each of said sets of links for retaining one of the respective segmental pins relatively fixed therein while affording clearance for the other pin in articulation.

9. A silent chain comprising a plurality of overlapping sets of links having aligned apertures, and articulating pintles mounted in the said aligned apertures, each pintle comprising a segmental part so arranged that its longitudinal edges are adapted to engage the edges of the apertures of one -set of links and so that its convex face is cooperatively associated with the other set of links whereby the chain stresses are transferred from one set of links to the other by pressure on said convex surface, said segmental element having a substantial portion of said concave side unsupported whereby the arch of the segment is permitted to depress under load and shock.

l0. A silent chain comprising a plurality of overlapping sets of links having aligned apertures, and articulating pintles mounted in said apertures each comprising two parts at least one of which is segmental in forni and arranged so that its longitudinal edges may engage the edges of said apertures and so that its convex side is cooperatively opposed to the other part, a substantial portion of the concave side of said segmental part being unsupported whereby the arch of the segment is permitted to depress under load and shock.

il. A silent chain comprising a plurality of overlapping sets of links having aligned apertures, and articulating pintles mounted in said apertures and joining said sets of links, each of said pintles comprising a pair of segmental elements with their edges opposed to the edges of said apertures and with their convex surfaces cooperatively opposed, means in one of said sets of links for holding one of the segmental elements relatively fixed while providing clearance for the other element in articulation, and means in the other f ,inks for retaining the other of said l elements relatively fixed therein rding clearance for the first-named element in articulation, a substantial portion of each of the concave sides of said elements being unsupported whereby the arches of said `egments are permitted to depress under load and shock.

l2. An articulating joint for silent chains 'comprising opposed pintle elements having cooperating surfaces adapted in articulation te roll one upon the other, at least one of said elements being resilient in a direction substantially normal to said surfaces at the point of contact.

13. A silent chain comprising a plurality of links arranged end to end in overlapping relation, and articulating joints for said links including opposed pintle elements having cooperatino` surfaces adapted in articulation to roll one upon the other, at least one of said elements being resilient in a direction substantially normal to said surfaces at the point of contact.

14. A silent chain comprising a plurality of links arranged end to end in overlapping relation, and pintle elements carried by the longitudinally adjacent links having cooperating surfaces adapt-ed to roll one upon the other for articulation, at least one of said elements being resilient in a direction substantially normal to said surfaces at the point of contact.

CHARLIE CARL ROTHMAN. 

